As with many items in home improvement, if you ask 10 different folks their opinions on the “best” methodology for applying exterior finishes to wood siding (shingles, clapboard, vertical siding, etc.), you may very well indeed get 10 different answers.
Being in business since 1995 and starting as someone whose primary focus was exterior painting, as you might imagine, I have experimented with many different finish application methodologies over the years.
After a long time of trying these differing application strategies, I can say with a high degree of confidence that the most longevity to be gained out of one’s exterior wood siding “paint” job, will be if the finishes are applied with a brush & roll strategy.
For the sake of our conversation here, when I mention the term “paint”, I am also wrapping in solid, semi-solid, and semi-transparent stains.
Certainly there are exceptions to this, but being that we guarantee everything that we do for 5 years after we do it, you can bet your bottom dollar that we are going to do everything we can possibly think of to maximize the longevity of any coating that we apply.
This being said, why is this?
When spraying your finish application on wood siding, even when “back-brushing/rolling” (the act of using a brush or roller to work the finish in after it is applied by spraying), the millimeter (mil) thickness of your coating will be markedly different throughout the wood siding surface being sprayed, due to the way paint ends up being absorbed varyingly by wood siding.
The closer to the center of the spray gun, the thicker the paint typically is landing on the surface and the further away from where the product is being sprayed from, typically the thinner the finish.
This is especially true the higher up on a building that one goes, particularly when spraying off a ladder.
No matter how well-intentioned the applicator, there is just no possible way to ensure an entirely even finish when approaching things in this manner due to how wood siding varies in the way it takes the product that is being applied to it.
Contrast this with applying your product with a brush or roller and you, literally, have 99%+ control over the entire structure that you are coating.
This is HUGE as it enables one to make sure that whosever’s home is being finished, is receiving as close as possible to an even and consistent finish coat throughout and systematically helps to ensure that the finish coat’s life is enabled to be maximized for as long as possible.
As mentioned, there are anomalies to this theory.
While I am the first to admit that coating the exterior of the home is much different than coating a car per se, there are instances when I am a believer in utilizing a sprayer to apply a finish coat (one example is, when similar to a car, one is painting aluminum or vinyl siding).
If finish coating shutters or lattice or something similar, spraying is absolutely the way to go.
These types of items are quite easy to ensure even and consistent finish coatings when being sprayed due to their tighter size when compared to the entire outside of a home or building.
Another ideal situation to utilize a spraying application is when applying certain types of non-film building water protectants, repellants, and sealers where mil thickness consistency is not a concerning focal point.
I am quite sure that there are many out there that would debate me profusely on this to one degree or another, which I am perfectly ok with.
After paying close attention for decades (at this point) however, it is quite evident to me what the best approach for guaranteeing the optimum life of one’s exterior paint job on wood siding is.
It may be easy to work up an argument against me, it is not as easy to work up an argument against the evidence.
